Fermentation Gas Injector Recycle Loop for Syngas Dispersion
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Solution Overview
Problem
The challenge in commercial-scale biofuel production from CO and H2/CO2 feed gas streams is the high hydrostatic pressure in deep fermentation vessels, which necessitates compressor use for gas dispersion, leading to energy-intensive operations and potential compressor damage from syngas impurities, while also causing inhibitory effects due to high CO and CO2 concentrations.
Innovation Solution
A recycle loop system that uses a gas injector to mix off-gas with fermentation liquid, creating a gas-liquid dispersion that is pumped downward, reducing the need for external compressors by leveraging hydrostatic pressure for absorption and compression, and includes a CO2 stripping vessel to control CO2 levels, utilizing the liquid product's surface tension reduction properties to maintain dispersion stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressors are used to pressurize syngas for injection into deep fermentation vessels, then gas dispersion and mass transfer are improved, but energy consumption increases and compressor reliability decreases due to damage from syngas impurities
Solution Approach 1:
The fermentation liquid itself serves as the pressurization medium. By pumping fermentation liquid from the bottom of the vessel back to the top through a gas injector, the system uses its own hydrostatic pressure to pressurize and disperse syngas into the liquid, eliminating the need for external compressors and reducing energy consumption while maintaining mass transfer efficiency
Solution Approach 2:
The invention employs hydraulic principles by using the circulation of fermentation liquid through a gas injector to create gas-liquid dispersion. The pumped liquid generates the necessary pressure to inject and disperse syngas bubbles throughout the fermentation volume, replacing mechanical compression with hydraulic action
2Ease of operation
If compressors are used to pressurize syngas, then gas injection into deep vessels is enabled, but device complexity and operational reliability worsen due to compressor vulnerability to impurities
Solution Approach 1:
The system uses its own fermentation liquid circulation to provide the pressurization function, making the fermentation process self-sufficient and eliminating vulnerable external compression equipment that would be damaged by syngas impurities
Solution Approach 2:
Fermentation liquid acts as an intermediary medium that transfers energy from the pump to the syngas injection process, enabling gas injection without direct mechanical compression and thereby protecting against reliability issues associated with compressor-impurity interactions
3Quantity of substance
If high hydrostatic pressure is present in deep fermentation vessels, then large volumes of liquid can be retained, but CO and CO2 concentrations increase to inhibitory levels
Solution Approach 1:
The system implements continuous circulation and periodic redistribution of fermentation liquid through pumping and re-injection, creating dynamic conditions that prevent localized accumulation of inhibitory CO and CO2 concentrations while maintaining overall high liquid volume
Solution Approach 2:
By making the fermentation liquid circulation dynamic through continuous pumping and re-injection at the top, the system actively manages gas concentration distribution, preventing static high-pressure conditions from causing harmful CO and CO2 accumulation in specific zones
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces CO and CO2 concentrations in the fermentation vessel, decreases compression requirements, and enhances mass transfer efficiency without the need for large compressors, improving the production of biofuels like ethanol by maintaining gas dispersion stability and absorption efficiency.
Implementation Method 1
A gas injector disperses a feed gas stream and a recycle gas stream into a gas-liquid dispersion
Implementation Method 2
the recycle loop employs a gas injector (dispersion device) to recover the off-gas from the vessel and mix gas with the recycle liquid to create a gas-liquid dispersion
Implementation Method 3
utilizing the liquid product's surface tension reduction properties to maintain dispersion stability
Data Source
AI summary
A process converts a gas input stream comprising CO, CO2, and H2 by contact with fermentation liquid into a liquid product that controls the concentration of CO and CO2 in the fermentation vessel. The process charges the feed gas stream and a recycle gas stream to the fermentation vessel and an off-gas stream collects above the fermentation liquid. The off-gas stream flows to a gas injector that uses a recycle liquid as the motive fluid to mix the off-gas with the recycle liquid into a gas-liquid dispersion. Contact of the recycle liquid with the off-gas absorbs CO2 to provide the recycle stream. A gas separation vessel separates the remainder of the off-gas into the recycle gas. Mixing the recycle gas with the gas input stream dilutes the concentration of CO to lower the CO concentration in the fermentation vessel. Separated recycle liquid flows to a CO2 stripper for removal of CO2.